PDP-11/93 and PMI Memory

Bill Gunshannon bill.gunshannon at hotmail.com
Thu Apr 18 20:20:38 CDT 2019

Well, I was finally able to get a PMI memory board to expand my
11/93 to the full 4 Meg.  (Thanks Paul!)

I thought it would be as simple as configuring what bank I wanted
it to fill and inserting it (in front of the CPU).  Sadly, that
didn't work.  First problem is the only document i could find is
not for the actual version of the board I  have.  It has the same
switch sets so I tried it anyway.  Set it to be in the upper 2Meg
and gave it the next CSR after the on board memory.  No luck.
11/93 still reports 1024KWords and the Map command shows neither
the additional memory or the second memory CSR.

Anybody have any experience with this? Is there a switch I have to
change on the CPU module to make it recognize the additional external
memory?  IS there something about PMI that I am missing?

Any advice gratefully appreciated.


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